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Breakthrough or Bunk?

Breakthrough or Bunk?

The breathless headlines proclaim this impossible engine could change space travel forever! Physicist John Baez explains the bad science behind the hype. 

#DebunkingJunkScience   #ScienceMediaHype  

Originally shared by John Baez

The incredible shrinking force

Around 2000, a guy named Robert Shawyer claimed he could bounce microwaves inside a fancy-shaped can and get them to  push the can forwards, without anything leaving the can. 

This would violate conservation of momentum.  It’s like sitting inside a car and making it roll forwards by pushing on the steering wheel.  Standard physics doesn’t allow this.  He didn’t claim to be using anything other than standard physics. 

So: ho hum, just another guy with a really bad idea.  I get emails like this all the time.

But in 2001, his company got a £45,000 grant from the British government to study this idea.  He built his machine and claimed that with 850 watts of power he could get a force of 0.016 newtons.   That’s a bit less than the force of gravity from a penny pushing down on your hand.  It could easily be an experimental error.

Why would people want a machine that uses lots of power to create a pathetically feeble force?   Because – here’s the great piece of salesmanship – if it existed, you could use it to build a reactionless drive!  If you had a spaceship with huge amounts of power to spare – like, say, a nuclear reactor – you could use this gizmo to push your spaceship forwards without anything spewing out the back end. 

Again, this is about as plausible as powering a spaceship by having the crew push on it from the inside.   But if you don’t know physics, it sounds very exciting. 

The story goes on.  And on.  And on.  It won’t die.  In 2012, some Chinese physicists claimed they could get a force of 0.720 newtons from a power of 2,500 watts using some version of Shawyer’s device. 

And now NASA is studying it!

They’re claiming to see a force one thousandth as big as the Chinese – maybe because they are doing the experiment one thousand times more accurately.  And still, some people are excited about this. 

The new device comes with new improved mumbo-jumbo.  Shawyer claimed that thanks to special relativity, classical electromagnetism can violate conservation of momentum.  I took those courses in college, I know that’s bullshit.  Now the NASA scientists say:

“Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.”

This is bullshit too – but now it’s grad school bullshit.  “Quantum vacuum virtual plasma” is something you’d say if you failed a course in quantum field theory and then smoked too much weed.  There’s no such thing as “virtual plasma”.   If you want to report experimental results that seem to violate the known laws of physics, fine.  But it doesn’t help your credibility to make up goofy pseudo-explanations.

I expect that in 10 years the device will be using quantum gravity and producing even less force. 

For an article written by a severely optimistic blogger, see:

The NASA technical report is here:

Unfortunately only the abstract is free!  I think someone with access should download the paper and make it publicly available.  If my government is spending my money on this sort of thing, I’d at least like to see it.


Join the Conversation


  1. Does John Baez know what quantum vacuum fluctuation are, or is he making shit up too?  Sounds like an argument of “I don’t understand it, so they can’t either, and  therefore it doesn’t exist”.

    I’d love to dig into the source about this.


  2. Nicholas Perry Baez posted a link to a full copy of the NASA study, just click through above to the original post by Baez that this post is a share of. After he posted the link he closed the comments to his post. 

    The NASA study gives every indication of supporting the proposed technology. 


  3. I think this works indeed and they also should know something that not everybody knows, what would give a huge advantage for those whom retain the knowledge, like the country, and they will not give everything to the open public for free any time soon. When they have perfected this sort of engine(the em engine), they will be the leader in many areas, (it’s easy to imagine cars without wheels, spaceships with anti-gravity rather rocket fuel based and even on military with missiles that doesn’t produce the signature like those used today). If they are telling thinks that doesn’t make sense for many of us and they did make it to work(note that it’s the third engine that works so far) this clearly imply that they know something and that quite few other people in the world knows. Also seems that those people that has the knowledge about this technology are in projects sponsored by governments and that those projects have double use, mean for civilian and military. So don’t expect anything explaining everything anytime soon.


  4. GoddardsJournal, I’m still on the fence. From the abstract at [ ], they make it pretty clear that they still need more evidence:

    “Test results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma. Future test plans include independent verification and validation at other test facilities.

    I find it strange that he leaves that last bit off – which seems to agree with him. Maybe he had a different abstract.

    Heated and potentially out of context remarks aside, I will have to agree with his stance on the media blowing this out of proportion.

    I’d like to mention that there is a good discussion on this over on /r/askscience:


  5. oh come on.   some nerd is trolling.  if i had come up with it, i would have never done it for fear of the joke falling flat due to no one taking it seriously to begin with.  file under ‘Gasoline Engine Made to Combust Water’


  6. GoddardsJournal you seem to be a NASA fan judging by your name and posts. But do you have a scientific rationale for your assertion that Dr. Baez is incorrect? We’d love to hear it! Also check out Brian Koberlain’s debunking post here:

    As Dr. Koberlain explains, the problem with the hypothesis is that “the more sensitive the experiment, the more the effect goes away.  This is a clear indication of experimental uncertainty rather than a real effect.”


  7. Science on Google+ Well, that was my comment right off the bat. But after reading the NASA study, Baez’s critique of it as well as other critiques, I’d say I’m either on the fence or siding with Baez. 

    Still, it should be noted that Baez doesn’t debunk the study in the sense that he’s uncovered an incontrovertible error that would account for the results. But he’s at least highlighted some questionable aspects of it, like that they didn’t achieve vacuum conditions as they desired. Moreover, they failed to make that shortfall clear, almost seeming to lead readers to erroneously believe that they did the tests in a vacuum by giving a detailed description of their atmospheric evacuation process. 

    So he’s raised good reasons to doubt the tests. We have to keep in mind these alleged drives are extraordinary claims and as such they require much more than the tiny bits of alleged evidence we have at hand now. 


  8. Glad that you backpedalled on your initial off the bat assessment 🙂 We brought this up because 5 people plussed your comment and presumably agreed with you. Here, at Science on Google+ , we want to encourage critical thinking and logic. Thanks! 


  9. Science on Google+ well, I don’t usually associate critical thinking and logic with automatically disagreeing with a team of NASA scientists. It’s also arguable that critical thinking allows for the possibility that future technologies, if we could see them today, would look like impossible magic even to contemporary physicists. To assume otherwise would be to assume that we’ve reached the end of all knowledge, an assumption I seriously doubt. 


  10. Ah, but the posts written by physicists on G+ critiquing the NASA paper were NOT “automatically disagreeing” with the idea. Instead, they carefully dissect the many problems associated with the study. Brian Koberlein concludes how “You can have the most beautiful theory in the world, but if experimental or observational evidence clearly contradicts it, then the theory fails”.

    Also check out Ethan Siegel ‘s fantastic discussion of this experiment in which he points out, “And finally (and most damning), there was a “true” version and a “null” version of the EmDrive that were both tested at this facility, with the anticipation that the true version would produce this thrust and that the null version wouldn’t. But both versions produced the same thrust.”


  11. Science on Google+ I’m not too impressed with the NASA study either (for reasons cited), but I don’t see anyone showing that its results clearly contradict the theory. In fact, the counter argument (at least Baez’s) amounts to a hypothesis that there’s some unknown interference that caused the results to be consistent with the theory. 


  12. simple problem deserve simple solution. Nobody claims the research isnt true, the problem is with the claims. I do not think they will be able to build thrust engine from the discovery but why not use the research results in order to build sequential gravity power. A device immitating the gravity force. if you check the amount of energy that is consumed by earth to keep one man standing on the ground maybe you will look at the numbers in the research differently.

    So maybe no new kind of energy engine but a way to add gravity to space travel. You never know.


  13. Althie Krehu Sorry, but the earth (or anybody else) does not consume any energy keeping one man standing on the ground.  Moving around is what consumes energy. 

    There is no suggested connection in this post with gravity, so somebody needs to invent a whole new thing for that – this one won’t help (not that it will help anything, I suspect).

    And I think you just made up the term ‘sequential gravity’.  Cute, though.


  14. Nick James for my knowledge the earth consume energy from the sun ( try to imagine heat source, calories is energy transfer unit) but not only from the sun. Without the sun there will a change in the basic operation of the earth core, the same core that is responsible for gravity. if somebody moves you it also consumes energy. About sequential gravity – ever heard about electromagnetism ? Do you know how AC (Alternating current Not Airconditioning) work?

    l’m glad nobody mentioned gravity before me, what is have to do with my knowledge and understanding?

    Somebody said something he was being criticized, I said something and I’m being criticized, why the remark about it won’t help anyone ?

    This discussion is about the necessity of the research not if it is right to stop research, if the idea is right but the conclusions are wrong what is better? to keep with the wrong conclusions or to stop researching the good idea?


  15. Althie Krehu LOL.  Time to stop digging, I think! 

    The bottom line on this post is that the proposed mechanism does not exist for most theoretical physicists.  Further, the experiments to demonstrate it at NASA read more like an end-of-term report concocted  in desperation after a long afternoon in the pub. There are so many holes in the report that it is more marketing hype than technical.  The fact that the non-functioning control item and the experimental object gave the same result says something is very wrong.  That they did not even test it in a vacuum opens the tests up to way too many sources of error and false positives, as they demonstrated. 

    And sequential gravity is still made up.  And is still a really cute-sounding idea.


  16. Nick James Well, you made me look :

    ” In order to arrive at geologically meaningful anomaly values, as series of “corrections” are made to raw observations of differences between gravity measured at a station and a base station. The use of this term is misleading because most of these “corrections” are really adjustments that compensate (at least approximately) for known variations in the gravity field that do not have geological meaning.”

    You dont need to agree with what is written, they just say there are “known variations in the gravity field that do not have geological meaning”, I decided to call these variation-sequence, and because it is about gravity I went with the phrase sequential gravity. Basically they are trying to measure gravity in a macro system (without the affect caused by instrument and measurement side effects). If you try to measure gravity you can do it by calculating the force between 2 masses or by calculating the environment known effect on mass at its presence. Due to changes in distance, vectors of forces, shape etc… the gravity that is measured is not precise, I believe that if you know the sequence of change in the measurement you will see coralating change in the gravity (I believe it is suppose to be sequential) , because in the research they don’t take account of it but prefer to stick to the formulas (classic way) we need more adventurer mind thinkers that will establish the new arguments in the classic equations.

    at least you like the sound of it 🙂


  17. Althie Krehu Good on you, going digging for real science:-)

    If you can make this work in a way that gives reliable numbers, that would be great.

    The reason that they “prefer to stick to the formulas (classic way)” is because they work and can be understood in how they work.  An awful lot of things were tried and discarded because they almost worked but did not.  And digging away at those things is how they improved it so that it did give a good and understood result – what you call the classic way.  It only became classic through a lot of hard work by people thinking in different ways.


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